What steps will reproduce the problem?

1.

public class Test {
 @SerializedName("a")
 public Integer b;
 public Double a;
}

2.

Test t = new Test();
t.b = 3;
gson.toJson(t)

What is the expected output? What do you see instead?

Expect: {"a":3}
Actual: {}

What version of the product are you using? On what operating system?

This works as expected in v1.2.2, but broke in one of the more recent builds.